In order to elongate life of tires mounted on a vehicle, change of positions of tires mounted on the vehicle, so-called rotation (position change) of tires, is performed according to the extent of wear of tire treads (surface of tire).
A tire having a tread wear indicator for indicating timing for the above rotation is known in conventional technologies disclosed in, for example, JP-A-55-110608, JP-UM-B-59-25684, or International Publication No. WO97/47483 (JP-T-10-511626).
In these conventional technologies, multi-step holes are formed as rotation timing indication holes in a tire tread, and when a first step of the hole disappears due to wear of the tire, it is determined as a time for rotation of the tire mounting position.
However, in these conventional technologies, since the contour of the rotation timing indication hole is formed in either a circle or a square, recognition of the step of the hole by a visual check is difficult, resulting in missing of a suitable rotation timing. For example, in a two-step hole having contours of double circles (⊙), even if the first step is worn to bring the contour of hole into a single circle (◯) a user may miss the change of the contour of the hole.